Resuscitation fluid

ABSTRACT

A method for treating conditions related to lack of blood supply with a lipid based resuscitation fluid is disclosed. The resuscitation fluid contains a lipid component and an aqueous carrier. The lipid component forms an emulsion with the aqueous carrier. The resuscitation fluid can be used to increase the blood pressure and to carry oxygen to tissues. The resuscitation fluid can also be used for preserving the biological integrity of donor organs for transplantation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Ser. No.12/314,737, filed Dec. 16, 2008, now allowed, which claims priority fromU.S. Provisional Application Ser. No. 61/016,443, filed Dec. 22, 2007and U.S. Provisional Application Ser. No. 61/064,639, filed Mar. 18,2008. The entirety of all applications are incorporated herein byreference.

FIELD

The technical field is medical treatment and, in particular, methods andcompositions for treating conditions related to lack of blood supply.

BACKGROUND

When a large amount of blood is lost, it is critical to immediatelyreplace the lost volume with a volume expander to maintain circulatoryvolume, so that the remaining red blood cells can still oxygenate bodytissue. In extreme cases, an infusion of real blood or blood substitutemay be needed to maintain adequate tissue oxygenation in the affectedindividual. A blood substitute differs from a simple volume expander inthat the blood substitute has the ability to carry oxygen like realblood.

Currently employed blood substitutes use either perfluorocarbons (PFCs)or hemoglobins as the oxygen carrier. PFCs are compounds derived fromhydrocarbons by replacing the hydrogen atoms in the hydrocarbons withfluorine atoms. PFCs are capable of dissolving relatively highconcentrations of oxygen. However, medical applications require highpurity perfluorocarbons. Impurities with nitrogen bonds can be highlytoxic. Hydrogen-containing compounds (which can release hydrogenfluoride) and unsaturated compounds must also be excluded. Thepurification process is complex and costly.

Hemoglobin is the iron-containing oxygen-transport metalloprotein in thered blood cells. Pure hemoglobin separated from red blood cells,however, cannot be used since it causes renal toxicity. Variousmodifications, such as cross-linking, polymerization, ad encapsulation,are needed to convert hemoglobin into a useful and safe artificialoxygen carrier. The resulting products, often referred to as HBOCs(Hemoglobin Based Oxygen Carriers), are expensive and have a relativeshort shelf-life.

Therefore, there still exists a need for a lower-cost resuscitationfluid that functions as a volume expander but is also capable ofcarrying a large amount of oxygen.

SUMMARY

A method for treating conditions related to lack of blood supply isdisclosed. The method includes administering to a subject in need ofsuch treatment an effective amount of a lipid based resuscitation fluidthat contains a lipid component and an aqueous carrier. The lipidcomponent forms an emulsion with the aqueous carrier.

Also disclosed is a method for preserving the biological integrity of anorgan of a mammalian donor organism. The method includes perfusing theorgan with an effective amount of a lipid based resuscitation fluidcontaining a lipid component and an aqueous carrier, wherein the lipidcomponent forms an emulsion with the aqueous carrier.

Also disclosed is a lipid based resuscitation fluid. The resuscitationfluid contains an oxygenated lipid emulsion and a buffering agent.

Also disclosed is a resuscitation kit. The resuscitation kit contains alipid based resuscitation fluid having a lipid component and an aqueouscarrier and an oxygenation device.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description will refer to the following drawings, whereinlike numerals refer to like elements, and wherein:

FIG. 1 is a diagram showing systolic blood pressure in mice treated withdifferent resuscitation fluids after severe hemorrhagic shock.

FIG. 2 is a diagram showing diastolic blood pressure in mice treatedwith different resuscitation fluids after severe hemorrhagic shock.

FIG. 3 is a diagram showing systolic blood pressure in mice treated witha resuscitation fluid of different volumes after severe hemorrhagicshock.

FIG. 4 is a diagram showing diastolic blood pressure in mice treatedwith a resuscitation fluid of different volumes after severe hemorrhagicshock.

FIG. 5 is a diagram showing a percentage of systolic blood pressure inmice treated with albumin-containing resuscitation fluids and micetreated with shed blood after severe hemorrhagic shock.

DETAILED DESCRIPTION

One aspect of the present invention relates to a resuscitation fluidcomposition for treating conditions related to lack of blood supply witha lipid based resuscitation fluid. The resuscitation fluid comprises alipid component and a polar liquid carrier. The lipid component isdispersed in the polar liquid carrier to form an emulsion that typicallycontains lipid micelles with a polar outer surface and an innerhydrophobic space. The resuscitation fluid can be used to increase bloodpressure and to carry oxygen to tissues.

Lipid Component

The lipid component can be any lipid that is capable of forming anemulsion with water. As used herein, the term “lipid” refers to anysuitable material resulting in a monolayer or lipid micelle in anaqueous environment such that a hydrophobic portion of the lipidmaterial orients toward the inner portion of the lipid micelle while ahydrophilic portion orients toward the aqueous phase. Hydrophiliccharacteristics derive from the presence of phosphato, carboxylic,sulfato, amino, sulfhydryl, nitro, and other like groups. Hydrophobicityis conferred by the inclusion of groups that include, but are notlimited to, long chain saturated and unsaturated aliphatic hydrocarbongroups, with such groups being optionally substituted by one or morearomatic, cycloaliphatic or heterocyclic group(s).

Examples of lipids include but are not limited to, fatty acyls,glycerolipids, phospholipids such as phosphatidylcholine (PC),phosphatidylethanolamine (PE), phosphatidic acid (PA),phosphatidylglycerol (PG), sphingolipids, sterol lipids such ascholesterol, prenol lipids, saccharolipids, polyketides, normaturallipid(s), cationic lipid(s) and mixtures thereof. In one embodiment, thelipid is a mixture of soybean oil and egg yolk phospholipids, such asthose used in Intralipid® (marketed and sold by Baxter InternationalInc., Deerfield, Ill.).

Polar Liquid Carrier

The polar liquid carrier can be any pharmaceutically acceptable polarliquid that is capable of forming an emulsion with the lipid. The term“pharmaceutically acceptable” refers to molecular entities andcompositions that are of sufficient purity and quality for use in theformulation of a composition or medicament of the present invention andthat, when appropriately administered to an animal or a human, do notproduce an adverse, allergic or other untoward reaction. Since bothhuman use (clinical and over-the-counter) and veterinary use are equallyincluded within the scope of the present invention, a pharmaceuticallyacceptable formulation would include a composition or medicament foreither human or veterinary use. In one embodiment, the polar liquidcarrier is water or a water based solution. In another embodiment, thepolar liquid carrier is a non-aqueous polar liquid such as dimethylsulfoxide, polyethylene glycol and polar silicone liquids.

A water-based solution generally comprises a physiologically compatibleelectrolyte vehicle isosmotic with whole blood. The carrier can be, forexample, physiological saline, a saline-glucose mixture, Ringer'ssolution, lactated Ringer's solution, Locke-Ringer's solution,Krebs-Ringer's solution, Hartmann's balanced saline, heparinized sodiumcitrate-citric acid-dextrose solution, and polymeric plasma substitutes,such as polyethylene oxide, polyvinyl pyrrolidone, polyvinyl alcohol andethylene oxide-propylene glycol condensates. The resuscitation fluid mayadditionally comprise other constituents such aspharmaceutically-acceptable carriers, diluents, fillers and salts, theselection of which depends on the dosage form utilized, the conditionbeing treated, the particular purpose to be achieved according to thedetermination of the ordinarily skilled artisan in the field and theproperties of such additives.

Plasma Component

The resuscitation fluid may further comprise a plasma component. In oneembodiment, the plasma is an animal plasma. In another embodiment, theplasma is human plasma. Although not wishing to be bound by anyparticular scientific theory, it is believed that the administration ofblood substitutes may dilute the concentration of coagulation factors toan undesirable level. Accordingly, using plasma as the diluent for theoxygen carrying component avoids this problem. Plasma can be collectedby any means known in the art, provided that red cells, white cells andplatelets are essentially removed. Preferably, it is obtained using anautomated plasmaphoresis apparatus. Plasmaphoresis apparatuses arecommercially available and include, for example, apparatuses thatseparate plasma from the blood by ultrafiltration or by centrifugation.An ultrafiltration-based plasmaphoresis apparatus such as manufacturedby Auto C, A200 (Baxter International Inc., Deerfield, Ill.) is suitablebecause it effectively removes red cells, white cells and plateletswhile preserving coagulation factors.

Plasma may be collected with an anticoagulant, many of which are wellknown in the art. Preferred anti-coagulants are those that chelatecalcium such as citrate. In one embodiment, sodium citrate is used as ananticoagulant at a final concentration of 0.2-0.5%, preferably 0.3-0.4%,and most preferably at 0.38%. It may be used in a range from The plasmamay be fresh, frozen, pooled and/or sterilized. While plasma fromexogenous sources may be preferred, it is also within the presentinvention to use autologous plasma that is collected from the subjectprior to formulation and administration of the resuscitation fluid.

In addition to plasma from natural sources, synthetic plasma may also beused. The term “synthetic plasma,” as used herein, refers to any aqueoussolution that is at least isotonic and that further comprises at leastone plasma protein.

Oncotic Agent

In one embodiment, the resuscitation fluid further contains an oncoticagent The oncotic agent is comprised of molecules whose size issufficient to prevent their loss from circulation by traversing thefenestrations of the capillary bed into the interstitial spaces of thetissues of the body. Examples of oncotic agents include, but are notlimited to, albumin such as human serum albumin, polysacchrides such asdextran, and polysacchride derivatives such as hydroxymethyl alpha (1,4) or (1, 6) polymers, Herastarch® (McGaw, Inc.) and cyclodextrins. Inone embodiment, the ontctic agent is about 5% (w/v) albumin. In anotherembodiment, the oncotic agent is a polysaccharide, such as Dextran, in amolecular weight range of 30,000 to 50,000 daltons (D). In yet anotherembodiment, the oncotic agent is a polysaccharide, such as Dextran, in amolecular weight range of 50,000 to 70,000 D. High molecular weightdextran solutions are more effective in preventing tissue swelling dueto their lower rates of leakage from capillaries. In one embodiment, theconcentration of the polysaccharide is sufficient to achieve (when takentogether with chloride salts of sodium, calcium and magnesium, organicion from the organic salt of sodium and hexose sugar discussed above)colloid osmotic pressure approximating that of normal human serum, about28 mm Hg.

Crystalloid Agent

The resuscitation fluid may also comprise a crystalloid agent. Thecrystalloid agent can be any crystalloid which, in the form of theresuscitation fluid composition, is preferably capable of achieving anosmolarity greater than 800 mOsm/1, i.e. it makes the resuscitationfluid “hypertonic”. Examples of suitable crystalloids and theirconcentrations in the resuscitation fluid include, but are not limitedto, 3% w/v NaCl, 7% NaCl, 7.5% NaCl, and 7.5% NaCl in 6% w/v dextran. Inone embodiment, the resuscitation fluid has an osmolarity of between 800and 2400 mOsm/1.

When the resuscitation fluid further comprises a crystalloid and ishypertonic, the resuscitation fluid may provide improved functionalityfor rapid recovery of hemodynamic parameters over other blood substitutecompositions, which include a colloid component. Small volume highlyhypertonic crystalloid infusion (e.g., 1-10 ml/kg) provides significantbenefits in the rapid and sustained recovery of acceptable hemodynamicparameters in controlled hemorrhage. (See, e.g., Przybelski, R. J., E.K. Daily, and M. L. Birnbaum, “The pressor effect of hemoglobin—good orbad?” In Winslow, R. M., K. D. Vandegriff, and M. Intaglietta, eds.Advances in Blood Substitutes. Industrial Opportunities and MedicalChallenges. Boston, Birkhauser (1997), 71-85). In another embodiment,the lipid emulsion used is Intralipid®. In another embodiment, the lipidemulsion used is 20% Intralipid®. In one embodiment, the lipid comprisesanti-inflammatory lipids such as omega-3 fatty acids.

Ion Concentrations

In one embodiment, the resuscitation fluid of the present inventionincludes a concentration of calcium, sodium, magnesium and potassium ionwhich is within the range of normal physiological concentrations of saidions in plasma. In general, the desired concentration of these ions isobtained from the dissolved chloride salts of calcium, sodium andmagnesium. The sodium ions may also come from a dissolved organic saltof sodium that is also in solution.

In one embodiment, the sodium ion concentration is in a range from 70 mMto about 160 mM. In another embodiment, the sodium ion concentration isin a range of about 130 to 150 mM.

In one embodiment, the concentration of calcium ion is in a range ofabout 0.5 mM to 4.0 mM. In another embodiment, the concentration ofcalcium ion is in a range of about 2.0 mM to 2.5 mM.

In one embodiment, the concentration of magnesium ion is in a range of 0to 10 mM. In another embodiment, the concentration of magnesium ion isin a range of about 0.3 mM to 0.45 mM. It is best not to includeexcessive amounts of magnesium ion in the resuscitation fluid of theinvention because high magnesium ion concentrations negatively affectthe strength of cardiac contractile activity. In a preferred embodimentof the invention, the solution contains subphysiological amounts ofmagnesium ion.

In one embodiment, the concentration of potassium ion is in asubphysiological range of between 0-5 mEq/1K⁺ (0-5 mM), preferably 2-3mEq/1K⁺ (2-3 mM). Thus, the resuscitation fluid allows for dilution ofthe potassium ion concentration in stored transfused blood. As a result,high concentrations of potassium ion and potential cardiac arrhythmiasand cardiac insufficiency caused thereby can be more easily controlled.The resuscitation fluid containing a subphysiological amount ofpotassium is also useful for purposes of blood substitution and lowtemperature maintenance of a subject.

In one embodiment, the concentration of chloride ion is in the range of70 mM to 160 mM. In another embodiment, the concentration of chlorideion is in the range of 110 mM to 125 mM.

Carbohydrates

The resuscitation fluid may also contain a carbohydrate or a mixture ofcarbohydrates. Suitable carbohydrates include, but are not limited to,simple hexose (e.g., glucose, fructose and galactose), mannitol,sorbitol or others known to the art. In one embodiment, theresuscitation fluid includes physiological levels of a hexose.“Physiological levels of a hexose” includes a hexose concentration ofbetween 2 mM to 50 mM. In one embodiment, the resuscitation fluidcontains 5 mM glucose. At times, it is desirable to increase theconcentration of hexose in order to lower fluid retention in the tissuesof a subject. Thus the range of hexose may be expanded up to about 50 mMif necessary to prevent or limit edema in the subject under treatment.

Buffering Agent

The resuscitation fluid of the present invention may further comprise abiological buffer to maintain the pH of the fluid at the physiologicalrange of pH7-8. Examples of biological buffers include, but are notlimited to, N-2-Hydroxyethylpiperazine-N′-2-hydroxypropanesulfonic acid(HEPES), 3-(N-Morpholino)propanesulfonic acid (MOPS),2-([2-Hydroxy-1,1-bis(hydroxymethyl)ethyl]amino) ethanesulfonic acid(TES),3-[N-tris(Hydroxy-methyl)methylamino]-2-hydroxyethyl]-1-piperazinepropanesulfonic acid (EPPS), Tris [hydrolymethyl]-aminoethane (THAM), andTris [Hydroxylmethyl]methyl aminomethane (TRIS).

In one embodiment, the buffering agent is histidine, imidazole,substituted histidine or imidazole compounds retaining the amphotericsite of the imidazole ring, oligopeptides containing histidine, ormixtures thereof. Histidine is also capable of reducing reactive oxygenspecies (see e.g., Simpkins et al., J. Trauma. 2007, 63:565-572).Histidine or imidazole is typically used in a concentration range ofabout 0.01M to 0.5M.

In another embodiment, the resuscitation fluid of the present inventionuses normal biological components to maintain in vivo biological pH.Briefly, some biological compounds, such as lactate, are capable ofbeing metabolized in vivo and act with other biological components tomaintain a biologically appropriate pH in an animal. The biologicalcomponents are effective in maintaining a biologically appropriate pHeven at hypothermic temperatures and at essentially bloodlessconditions. Examples of the normal biological components include, butare not limited to carboxylic acids, salt and ester thereof. Carboxylicacids have the general structural formula of RCOOX, where R is an alkyl,alkenyl, or aryl, branched or straight chained, containing 1 to 30carbons which carbons may be substituted, and X is hydrogen or sodium orother biologically compatible ion substituent which can attach at theoxygen position, or is a short straight or branched chain alkylcontaining 1-4 carbons, e.g., —CH₃, —CH₂ CH₃. Examples of carboxylicacids and carboxylic acid salts include, but are not limited to, lactateand sodium lactate, citrate and sodium citrate, gluconate and sodiumgluconate, pyruvate and sodium pyruvate, succinate and sodium succinate,and acetate and sodium acetate.

Other Components

In addition to the components discussed above, the resuscitation fluidmay further comprise other additives such as antibiotics, vitamins,amino acids, vessel expanders such as alcohols and polyalcohols,surfactants, and antibodies against harmful cytokines such as tumornecrosis factor (TNF) or interleukins. In addition, other gases, such ashydrogen sulfide which is a regulator of blood pressure, or carbonmonoxide which has cytoprotective properties that can be used to preventthe development of pathologic conditions such as ischemic reperfusioninjury, may be added.

Preparation of the Resuscitation Fluid

The resuscitation fluid may be prepared by mixing the lipid component,the aqueous carrier, and any other components to form an emulsion.Commonly used mixing methods include, but are not limited to, stirring,shaking, vibration and sonication. In one embodiment, the resuscitationfluid is formed by mixing a pre-formed lipid emulsion, such asIntralipid®, with the aqueous carrier and other components.

In order to increase the oxygen content in the resuscitation fluid, theresuscitation fluid may be oxygenated by bubbling pure oxygen or a gaswith an oxygen content in the range of 21% to 100% (v/v), preferably 40%to 100% (v/v), more preferably 60% to 100% (v/v), and most preferably80% to 100% (v/v), through the resuscitation fluid for a period of 30seconds or longer, preferably 1-15 minutes, more preferably 1-5 minutes.The oxygenation time for a resuscitation fluid of a particularcomposition may be determined experimentally. In one embodiment, theresuscitation fluid is oxygenated immediately prior to application.

In one embodiment, the resuscitation fluid comprises an oxygenated lipidemulsion. As used herein, the term “oxygenated lipid emulsion’ or“oxygenated resuscitation fluid” refers to a specific type of gassedlipid emulsion or gassed resuscitation fluid which has been forced toabsorb oxygen such that the total concentration of oxygen containedtherein is greater than that present in the same liquid at atmosphericequilibrium conditions.

Kits

Another aspect of the present invention relates to a resuscitation kit.In one embodiment, the resuscitation kit comprises an oxygenatedresuscitation fluid and at least one additive. Examples of additivesinclude, but are not limited to, oncotic agent, crystalloid agent,vessel expander, cardioplegic, or cardiotonic agent scavengers of freeradicals or mediators, cell signaling modulators, and receptor agonistsor antagonists. In another experiment, the kit further contains anintravenous infusion (IV) set. In another embodiment, the oxygenatedresuscitation fluid is contained in one or more preloaded syringes foremergency application. In another embodiment, the kit further containsan oxygen container that can be used to re-oxygenate the resuscitationfluid immediately prior to application. The oxygen container may containpure oxygen, or a gas mixture of oxygen with either hydrogen sulfide orcarbon monoxide or both. In another embodiment, the kit contains aresuscitation fluid, and an air pump for oxygenating the resuscitationfluid with ambient air immediately prior to application.

Treatment Methods

Another aspect of the present invention relates to a method for treatingconditions related to lack of blood supply with a lipid-basedresuscitation fluid. Conditions related to a lack of blood supplyinclude, but are not limited to, hypovolemia, ischemia, hemodilution,trauma, septic shock, cancer, anemia, cardioplegia, hypoxia and organperfusion. The term “hypovolemia,” as used herein, refers to anabnormally decreased volume of circulating fluid (blood or plasma) inthe body. This condition may result from “hemorrhage,” or the escape ofblood from the vessels. The term “ischemia,” as used herein, refers to adeficiency of blood in a part of the body, usually caused by afunctional constriction or actual obstruction of a blood vessel.

The resuscitation fluid may be administered intravenously orintraarterially to a subject in need of such treatment. Administrationof the resuscitation fluid can occur for a period of seconds to hoursdepending on the purpose of the resuscitation fluid usage. For example,when used as a blood volume expander and an oxygen carrier for thetreatment of severe hemorrhage shock, the usual time course ofadministration is as rapidly as possible, which may range from about 1ml/kg/hour to about 15 ml/kg/min. When used for organ perfusion duringan organ transplantation, the resuscitation fluid may be administeredslowly over a period of hours.

While the resuscitation fluid of the present invention is beingadministered to and circulated through the subject, various agents suchas cardioplegic or cardiotonic agents may be administered eitherdirectly into the subject's circulatory system, administered directly tothe subject's myocardium, or added to the resuscitation fluid of thepresent invention. These components are added to achieve desiredphysiological effects such as maintaining regular cardiac contractileactivity, stopping cardiac fibrillation or completely inhibitingcontractile activity of the myocardium or heart muscle.

Cardioplegic agents are materials that cause myocardial contraction tocease and include anesthetics such as lidocaine, procaine and novocaineand monovalent cations such as potassium ion in concentrationssufficient to achieve myocardial contractile inhibition. Concentrationsof potassium ion sufficient to achieve this effect are generally inexcess of 15 mM.

During revival of a subject, the subject may be re-infused with amixture of the resuscitation fluid described along with blood retainedfrom the subject or obtained from blood donors. Whole blood is infuseduntil the subject achieves an acceptable hematocrit, generally exceedinghematocrits of about 30%. When an acceptable hematocrit is achieved,perfusion is discontinued and the subject is revived after closure ofsurgical wounds using conventional procedures.

Another aspect of the present invention relates to a method ofpreserving the biological integrity of organs of a mammalian donororganism. using the resuscitation fluid described. In one embodiment,the subject organ is chilled and the resuscitation fluid is perfusedinto the subject organ using a pumped circulating device such as acentrifugal pump, roller pump, peristaltic pump or other known andavailable circulatory pump. The circulating device is connected to thesubject organ via cannulae inserted surgically into appropriate veinsand arteries. When the resuscitation fluid is administered to a chilledsubject organ, it is generally administered via an arterial cannula andremoved from the subject via a venous cannula and discarded or stored.

EXAMPLES

The following example is put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how tocarry out the method of the present invention and is not intended tolimit the scope of the invention. Efforts have been made to ensureaccuracy with respect to numbers used (e.g., amounts, temperature,etc.), but some experimental error and deviation should be accountedfor. Unless indicated otherwise, parts are parts by weight, molecularweight is weight average molecular weight, temperature is in degreesCentigrade, and pressure is at or near atmospheric.

Example 1 Methods and Materials

Lipid emulsion: 20% Intralipid (marketed and sold by BaxterInternational Inc., Deerfield, Ill.) was used as a model lipid emulsion.It is composed of 20% soy bean oil, 1.2% egg yolk phospholipids 2.25%glycerin, water and sodium hydroxide to adjust the pH to 8.

Determination of oxygen content of Intralipid: Samples of distilledwater, Ringer's lactate (RL) and Intralipid (20%) (1 ml each) were leftopen to air in 2.0 ml tubes for 30 minutes prior to dissolved gasanalysis. Volumes of 50 uL drawn from each of these fluids were injectedinto a Sievers purge vessel at 37° C. containing 36 ml of a mildlyacidic solution consisting of 32 ml of 1M HCL and 4 ml of 0.5M ascorbicacid. The solution was continuously purged with high purity helium totransport any oxygen released from the samples to a mass spectrometer(HP 5975) for direct gas analysis. Signals generated at m/z=32 uponinjection of RL and lipid emulsion samples were integrated using Peakfitand compared to those obtained with distilled water.

Animals and animal procedures: Male and female mice weighing 27-47 gramswere utilized. The strains were either CD-1 or NFR2. All comparisonsutilized the same strain. Mice were anesthetized using ketamine/xylazineanesthesia administered subcutaneously. In order to prevent the skewingof data due to the cardiodepressant effects of the anesthetic agent, theexperiment was aborted and the mouse euthanized in the rare instancewhen more anesthetic was required than the calculated dose. Once it wasclear that the mouse was well-anesthetized, the carotid artery wascannulated. As much blood as possible was removed in one minute. Thisresulted in the loss of 55% of blood volume and 100% lethality withoutany infusion. Immediately after blood removal infusions wereadministered over one minute.

Either RL or Intralipid was administered at a volume equal to the amountof blood that had been removed. Blood pressure was measured at thecarotid artery using a BP-2 monitor made by Columbus Instruments(Columbus, Ohio). This monitor measures the blood pressure as a voltage.A standard curve was prepared. Measured voltages were converted to bloodpressure (BP) using the following formula:

BP=[Voltage−0.1006]/0.0107

No warming measures were applied to the mice. No measures were taken tosupport respiration.

Statistical Analysis: Data were analyzed using Student's unpaired ttest.

Example 2 Oxygen Content of the Resuscitation Fluid

Intralipid® 20% I.V. Fat Emulsion (marketed and sold by BaxterInternational Inc., Deerfield, Ill.) was used as a sample resuscitationfluid (RF). The composition of Intralipid® is 20% soybean oil, 1.2% eggyolk phospholipids, 2.25% glycerin, water and sodium hydroxide to adjustthe pH to 8. Oxygen content in the RF was measured using massspectrometry. As shown in Table I, the oxygen content of the RF wasnearly twice that of Ringer's lactate (RL), a standard resuscitationfluid infused when a large amount of blood is lost. The oxygen contentof RL was equivalent to that of water. As shown in Table II, the oxygencontent of the RF was increased five-fold by bubbling oxygen through itfor approximately 1 minute. After oxygen loading, the oxygen content ofRF compared favorably to that of blood with the minimum acceptablehemoglobin level (i.e., 7.0 g/dl). Table III shows that theoreticaloxygen content in RF with higher lipid contents.

TABLE I Oxygen content of Ringer's lactate and Intralipid ® 20% Ringer'slactate Intralipid ® 20% Oxygen Content* 0.91 ± 0.11* 1.78 ± 0.09* *theoxygen content is expressed as the amount relative to the oxygen contentin water.

TABLE II Oxygen solubility in various liquids at 1 atm Oxygen Content at25° C. and Sea level Pressure Blood (hemoglobin of 7.0) 72.8 mg/L Water 8.3 mg/L LM (20%) 15.1 mg/L LM (20% after oxygen perfusion) 75.5 mg/L

TABLE III Theoretical oxygen content in RF with higher lipidconcentrations Theoretical oxygen content at higher concentrations LM(40%)  24.9 mg/L LM (40% after oxygen perfusion) 124.5 mg/L LM (60%) 33.2 mg/L LM (60% after oxygen perfusion) 166.0 mg/L

Example 3 The Effect of Resuscitation Fluid in Restoring ArterialPressure in Mice with Severe Hemorrhagic Shock

The effect of the RF in Example 2 on blood pressure was determined inmice. Mice were anesthetized and a cannula was placed into the carotidartery. All the blood that could be removed was removed via the carotidartery. After the blood was removed a volume of either RL or RF wasgiven equal to the amount of blood removed. 6 mice were in the RF groupand 6 mice were in the RL group. The observation period was one hour.Two of the mice given RL died within ten minutes. All mice given RFlived through the entire hour observation period and until euthanized at1-4 hours. Animals were euthanized whenever they began to awaken fromthe anesthesia or at the end of the observation period to preventsuffering.

FIGS. 1 and 2 show the difference between the systolic blood pressure(FIG. 1) and diastolic blood pressure (FIG. 2) after hemorrhage andafter infusion of RL or RF at time=0, 30 and 60 minutes. The Y axisrepresents the blood pressure attained after infusion minus the bloodpressure after hemorrhage in mm of Hg. The X axis shows the specifictime after the infusion. All data were analyzed for statisticalsignificance using an unpaired two tailed t test. These graphs show thatRF raised the blood pressure higher than RL.

In another experiment, RF at a volume twice the amount of blood removedwas given. This led to an even greater increase in the blood pressure asshown in FIGS. 3 and 4. The points on the graph represent the mean of 6mice+/−SE. The Y-axis shows the difference between the systolic bloodpressure (FIG. 3) and diastolic blood pressure (FIG. 4) after infusionof RF at 1× the blood volume (diamond) or 2× the blood volume (square)minus the baseline pressure prior to hemorrhage in mm of Hg. Under thisscheme therefore, 0 represents the blood pressure at the beginning ofthe experiment before hemorrhage. The X axis shows specific times afterthe infusion. 2× the blood volume raised the blood pressure higher thanthe pressure reached after infusion of 1× the blood volume (p<0.01).Moreover, the pressure achieved after infusion of 2× the removed bloodvolume exceeded the pressure that existed prior to hemorrhage.

In another experiment, a resuscitation fluid containing Intralipid® 20%and 5% (w/v) albumin was prepared by dissolving albumin (Sigma Aldrich,99% pure, fatty acid free, essentially globulin free, catalog numberA3782-5G) in Intralipid® 20% to a final concentration of 50 mg/ml. Thenew resuscitation fluid with albumin (RFA) was tested using theexperimental procedure described above. Albumin dissolved in normalsaline (NSA) and Ringer's lactate (RLA) at 50 mg/ml, as well as the shedblood (i.e., the blood that had been removed from the mice), were usedas controls. In FIG. 5, the Y axis shows the percentage of the systolicblood pressure prior to hemorrhage achieved by infusion of the variousfluids. The X axis shows specific times after the infusion. The datashow that RFA is superior even to shed blood in maintaining bloodpressure. Similar results were also obtained for the diastolic bloodpressure (not shown). For each time point, an average of 6-7 mice isplotted. Differences between shed blood and RFA was statisticallysignificant (P<0.05) at 5, 15 and 30 minutes.

These experimental results are consistent with the fact that the lipidmicelles in the resuscitation fluid are capable of exerting an osmoticforce and absorbing mediators of vascular potency, such asprostaglandins, nitric oxide, leukotrienes, and platelet activatingfactors.

The terms and descriptions used herein are set forth by way ofillustration only and are not meant as limitations. Those skilled in theart will recognize that many variations are possible within the spiritand scope of the invention as defined in the following claims, and theirequivalents, in which all terms are to be understood in their broadestpossible sense unless otherwise indicated.

1. A method for raising blood pressure in a human or animal subject withhypovolemia or ischemia, comprising: administering to said subject aneffective amount of a lipid based resuscitation fluid comprising a lipidcomponent and an aqueous carrier, wherein said lipid component forms anemulsion with said aqueous carrier in the form of lipid micelles with apolar outer surface and an inner hydrophobic space.
 2. (canceled)
 3. Themethod of claim 1, wherein said resuscitation fluid further comprises aplasma component.
 4. The method of claim 3, wherein said plasmacomponent is albumin.
 5. The method of claim 4, wherein said albumin hasa final concentration of approximately 5% (w/v).
 6. The method of claim1, wherein said resuscitation fluid further comprises at least oneadditive selected from the group consisting of oncotic agents,crystallioid agents, buffering agents, carbohydrates, salts, vitamins,antibodies, and surfactants.
 7. The method of claim 1, wherein saidresuscitation fluid further comprises a buffering agent.
 8. The methodof claim 7, wherein said buffering agent comprises histidine at aconcentration of between 0.01 M to 0.2M.
 9. The method of claim 1,further comprising: oxygenating the lipid based resuscitation fluidprior to administration to said subject.
 10. The method of claim 9,wherein said lipid based resuscitation fluid is oxygenated by bubblingan oxygen-containing gas through the lipid based resuscitation fluid for1 to 5 minutes.
 11. The method of claim 9, wherein said lipid basedresuscitation fluid is oxygenated by bubbling a gas comprising 90%-100%(v/v) oxygen through the lipid based resuscitation fluid for about 1minute.
 12. The method of claim 1, wherein said resuscitation fluid isadministered either intravenously or intra-arterially. 13-29. (canceled)